Sinking of the RMS Lusitania

The Sinking of the RMS Lusitania occurred on 7 May 1915 when a German U-boat torpedoed and sank the British Cunard ocean liner RMS Lusitania off the coast of Kinsale, Ireland, killing 1,198 of the 1,959 passengers on board. The sinking of the Lusitania occurred during the German Empire's "unrestricted submarine warfare" campaign of World War I, and they claimed that the ship was carrying British armaments. The sinking of the Lusitania caused international opinion to turn against Germany, and it ultimately led to the United States joining the war on the side of the Entente in 1917.

Background
After its defeat at the Battle of the Falkland Islands, the Imperial German Navy started using submarines to attack Allied shipping. Germany's submarines were initially intended for use in coastal defense and to sink British warships. The German Navy planned to use surface commerce raiders against Allied merchant shipping. However, after Germany's decisive defeat at the Battle of the Falkland Islands in December 1914, its ability to threaten Allied commerce with surface vessels was curtailed.

While trade to Britain was unimpeded, the Royal Navy maintained a maritime blockade of Germany. In November 1914, the British declared the North Sea a war zone, which German ships would enter at their peril. German submarines began attacks against British merchant shipping. The first merchant ship destroyed by a German U-boat was the steamship SS Glitra, sunk off Norway on 20 October 1914.

History
Germany began discussing the possibility of a systematic submarine campaign against merchant shipping in the late autumn of 1914. The U-boat fleet numbered only a few dozen boats, but they were proving capable of attacks on merchant ships in the North Sea. Submarine commanders were resepecting accepting "prize rules", which meant they had to surface, stop a ship, and allow its crew and passengers to disembark before sinking it. If a more intensive campaign was to be mounted, U-boats would need permission to attack without warning, firing torpedoes while submerged. The risk of outraging neutral opinion in doing this, especially in the United States, was outweighed by the need for a more effective response to Britain's naval blockade.

Easy prey
On 4 February 1915, Germany announced that Allied merchant ships in waters around Britain and Ireland were liable to be sunk and it would be impossible "to avert the danger thereby threatened to crew and passengers." About 20 U-boats were dispatched to seek suitable targets. With no convoy system in place, isolated merchant ships were easy prey. On 22 April, the German embassy in Washington DC published a warning to passengers intending to cross the Atlantic on the British liner Lusitania, reminding them that ships entering the war zone around the British Isles were liable to be destroyed. Nevertheless, on 1 May, the liner left New York for Liverpool with almost 2,000 people on board. In the hold was a small amount of military cargo, chiefly rifle ammunition.

On the afternoon of 7 May, Captain Walther Schwieger, commanding the submarine U-20, sighted the Lusitania off the south coast of Ireland. The U-boat was too slow to mount a pursuit, especially when it was submerged to attack, but the liner turned into its path. Schwieger struck the Lusitania with a single torpedo in the center of the ship. Desperate attempts to launch the ship's lifeboats were cut short when the liner sank only 18 minutes after being hit.

The death toll of 1,198 consisted of 785 passengers and 413 crew. Almost 100 of the victims were children, and 128 were US citizens. Germany tried in vain to argue that the Lusitania was a legitimate target. To most people in Allied and neutral countries, the sinking appeared to be straightforward mass murder. There were riots in cities in Britain and its dominions, with German-owned shops looted. The worst disorders occurred in the city of Liverpool, where many of the crew had lived.

The American president, Woodrow Wilson, responded to the attack with a series of indignant notes to the German government, in which the sinking was denounced as illegal and counter to "the rights of humanity." Germany was left in little doubt that if it continued attacking unarmed merchant ships - especially passenger ships - without warning, then the United States might be provoked into entering the war. The submarine campaign was not immediately suspended, but U-boat commanders were ordered to take care in choosing targets and follow prize rules where possible.

British tactics
To counter the submarine campaign, Britain's merchant ships flew the flags of neutral countries, knowing that U-boats had orders to avoid sinking neutral ships. Merchant captains were encouraged to fight back if stopped by a U-boat in accordance with prize rules, a form of self-defense that outraged the Germans. In the summer of 1915, the Royal Navy began equipping innocent-looking merchant steamers with hidden guns. These Q-ships, as they were called, lured U-boats into making a surface attack and then blasted them out of the sea. This tactic encouraged the Germans to make submerged attacks without warning, which the British could then denounce as immoral.

Aftermath
The German U-boat campaign continued into early 1916, further antagonizing the United States. On 19 August 1915, a German U-boat sank the White Star liner Arabic, killing 44 people, including three Americans. On the same day, a U-boat was sunk by the British Q-ship Baralong and all the survivors were executed. President Wilson, more concerned by the Arabic sinking, obtained a German pledge to avoid further attacks on passenger ships. However, in March 1916, a U-boat sank the ferry Sussex in the English Channel. Germany was temporarily deterred from submarine warfare by hostility in the US. Renewed attacks in February 1917 led to the US joining the war.